Canada doesn't sit on the sidelines while its allies shoulder the burden of tackling global threats, Stephen Harper said Friday as he insisted that it's a U.S. request for help in Iraq that has him contemplating a bigger role.Whatever jobs Canada does end up doing in the current crisis in the Middle East, it will take them on with "no reluctance" because the Islamic State of Iraq and the Levant poses a significant threat to Canadian security, the prime minister said."There is a real threat against us," an animated Harper, flanked by European leaders in town to cement their new trade relationship with Canada, told a news conference on Parliament Hill. "We cannot have a terrorist caliphate controlling a large swath of territory and carrying out terrorist attacks against targets here and around the world. We cannot accept that."Harper congratulated the United States and other allies for their actions in Iraq and Syria. "But when we support something because it is necessary and desirable, then we have to do our part," he continued. "That's the history of Canada. We don't just stand on the sidelines. That would be completely irresponsible."Harper touched off a firestorm earlier this week when he revealed during a visit to New York that the U.S. had recently asked Canada to expand its role in the battle against the marauding al-Qaida splinter group known as ISIL.A INVC News report Thursday, however, suggested that the U.S. request was actually in response to a Canadian overture to play a more significant role in the ongoing mission.Before Harper spoke, U.S. ambassador to Canada Bruce Heyman said Washington asked Canada for help, insisting that the sequence of conversations and communications between the two countries is of no matter. "We asked Canada to join the global coalition against ISIL, just as we have other close partners," Heyman said in an interview with The Canadian Press."And we are incredibly, as you can imagine, grateful for the steadfast commitment that Canada has provided."Shortly after the Global report appeared, officials from the Prime Minister's Office insisted that if Washington was responding to anything, it was an earlier commitment from Canada to seriously consider any request for help."I find this kind of bizarre," Harper said. "Is this seriously suggesting that Canada is dragging the U.S. into military conflict? Let's be serious here." Heyman said the two countries have had a number of high-level discussions about collaboration."We're actually not delineating in public conversation exactly what we're asking for. We're leaving that to dialogue and conversations between our two governments. But we are asking very specifically for additional support and help at whatever level Canada feels comfortable providing."Harper said the American requests are under consideration. "We will always make our own decision, but we will make those decisions based on our capacity and based on our objectives. Ultimately, it is not our intention not to support our allies." Foreign Affairs Minister John Baird said Thursday that if Canada were to contemplate playing a combat role, such as participating in airstrikes, it would be subject to a vote in Parliament.